The present disclosure relates generally to automotive electrical systems and, more particularly, to a dual voltage architecture for automotive electrical systems.
The increasing power demands on motor vehicle electrical systems as a result of added loads such as electric power steering and other customer convenience features has made it difficult to efficiently generate and distribute power with a traditional 12-volt battery/14-volt generator system. For example, in a luxury vehicle having electric power steering and instant PTC (positive temperature coefficient) heaters, the demand for power generation can be as much as 3.5 kW during normal operation and about 2.5 kW at enhanced idle speed. Thus, in order to continue to meet this increased power demand while maintaining/improving system operating efficiency, the automotive industry has begun to focus on implementing 42-volt systems.
However, one difficulty in converting the electrical system of vehicle to a higher voltage such as 42 volts stems from the fact that all of the vehicle's associated electrical loads, components, connectors, relays, etc. would necessarily have to be redesigned in order to accommodate the higher operating voltage. As such, a more likely scenario calls for a “transition period” in which vehicles will include both 14-volt and 42-volt components supplied by a corresponding hybrid (i.e., dual voltage) electrical system. In fact, there are several proposed dual voltage systems in existence that provide both a 14-volt operating voltage and a 42-volt operating voltage for a motor vehicle.
Unfortunately, many of these existing dual voltage systems have been designed without particular regard to packaging, space, cost and/or redundancy concerns. For example, certain dual voltage systems provide for two separate batteries (one for each operating voltage), while others employ expensive inverter circuitry associated with a higher voltage generator.